The present invention relates to a discrimination device to discriminate variations in the magnitudes of colors so that the variations of magnitudes of color differences, if any, on the painted surface of an object or on the colored surface of a dyed clothe can be perceived by employing the same basis as that used by a human being to discriminate a certain type of color difference.
Variations in the magnitudes of color differences found in paintings, dyes and printing have discriminated by the subjective decision made by an observer in charge of such work.
Even if variations are found in wavelength from the designated color, no variations of magnitudes of color differences are specified to be detected by the customer when the variations are within a certain range wherein no variations of magnitudes of color differences are sensationally perceived. Unless the variations of magnitudes of color differences can be perceived by an observer with normal sensation, they are not specified to be detected even if they can be measured.
This type of decision has been made by the worker who is skillful due to his many experiences.
Devices and systems which automatically acquire continuous data for making a decision regarding colors have been proposed prior to the present invention, and they include Japanese Laid-Open Patent Applications No. Hei 1-141326 entitled Colorimetric Method, No. Hei 2-51032 entitled Color Shade Evaluating Method for Color Molded Product, Hei 2-114134 entitled Color Identification Device, and Hei 2-73122 entitled Continuous Colorimetry Instrument.
Variations in the magnitude of colors have not been considered in the detection devices described heretofore. Although data has been obtained for the magnitudes of colors, the variations of magnitudes of color differences cannot be discriminated by the obtained data.
The ability to discriminate between the variations in the magnitudes of color differences, which means the range in which the variations of magnitudes of color differences can be discriminated, depends on the characteristics of the eyes of the person making the discrimination. The ability to discriminate the variations of magnitudes of color differences by a person having blue eyes has been compared with that of a person having dark eyes on the basis of the fact that the ability to discriminate the variations of magnitudes of color differences depends on the color of the eyes of the observer.
Data which indicates the capability of discriminating the hue by a person having dark eyes has been obtained.